mpc85xx: support for Freescale COM Express P2020

This adds support for the Freescale COM Express P2020 board. This board
is similar to the P1_P2_RDB, but has some extra (as well as missing)
peripherals.

Unlike all other mpc85xx boards, it uses a watchdog timeout to reset.
Using the HRESET_REQ register does not work.

This board has no NOR flash, and can only be booted via SD or SPI. This
procedure is documented in Freescale Document Number AN3659 "Booting
from On-Chip ROM (eSDHC or eSPI)." Some alternative documentation is
provided in Freescale Document Number P2020RM "P2020 QorIQ Integrated
Processor Reference Manual" (section 4.5).

Signed-off-by: Ira W. Snyder <iws@ovro.caltech.edu>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
diff --git a/boards.cfg b/boards.cfg
index 8608b0e..84cf6b2 100644
--- a/boards.cfg
+++ b/boards.cfg
@@ -717,6 +717,8 @@
 P2020RDB-PC_36BIT_NAND       powerpc     mpc85xx     p1_p2_rdb_pc        freescale      -           p1_p2_rdb_pc:P2020RDB,36BIT,NAND
 P2020RDB-PC_36BIT_SDCARD     powerpc     mpc85xx     p1_p2_rdb_pc        freescale      -           p1_p2_rdb_pc:P2020RDB,36BIT,SDCARD
 P2020RDB-PC_36BIT_SPIFLASH   powerpc     mpc85xx     p1_p2_rdb_pc        freescale      -           p1_p2_rdb_pc:P2020RDB,36BIT,SPIFLASH
+P2020COME_SDCARD             powerpc     mpc85xx     p2020come           freescale      -           P2020COME:SDCARD
+P2020COME_SPIFLASH           powerpc     mpc85xx     p2020come           freescale      -           P2020COME:SPIFLASH
 P2041RDB                     powerpc     mpc85xx     p2041rdb            freescale
 P2041RDB_SDCARD              powerpc     mpc85xx     p2041rdb            freescale      -           P2041RDB:RAMBOOT_PBL,SDCARD,SYS_TEXT_BASE=0xFFF80000
 P2041RDB_SECURE_BOOT         powerpc     mpc85xx     p2041rdb            freescale      -           P2041RDB:SECURE_BOOT